Thermal forming preparation method of carburizing part and thermal forming carburizing part

Abstract

The invention discloses a thermal forming preparation method of a carburizing part and a thermal forming carburizing part, belongs to the technical field of metal material surface chemical heat treatment strengthening, and solves the problems that surface carburizing heat treatment of a traditional part needs extremely long in-furnace diffusion time, the production efficiency is relatively low and the energy consumption is high. The preparation method comprises the steps that carburizing steel is subjected to preforming treatment through a hot working method, and a part blank is obtained; performing cold rough machining on the part blank; the part blank is subjected to carburizing treatment, and a carburized layer with the depth larger than 2 mm is obtained; the discharged part blank is subjected to die forging precision forming and subsequent heat treatment, and a thermally-formed carburized part is obtained; and the thermal forming carburizing part is subjected to accurate grinding machining, and the target size is achieved. The method can be used for heavy-duty gears, shafts, bearings and other parts needing deep carburized layers.

Description

Technical Field

[0001] The invention relates to the technical field of metal material surface chemical heat treatment strengthening, and in particular to a hot forming preparation method for a carburized component and a hot formed carburized component. Background Art

[0002] Under heavy load conditions, key mechanical parts such as gears, shafts, and bearing support rings need to obtain a deep carburized layer on their service surfaces, and achieve excellent contact fatigue wear resistance through subsequent phase transformation toughening. However, for the technical requirements of carburized layers above 3 mm, traditional surface carburizing heat treatment usually requires a very long diffusion time in the furnace, low production efficiency, and huge energy consumption.

[0003] In the existing technology, the carburizing process can be accelerated by adjusting the ratio of strong carburizing and diffusion cycles, carbon potential matching, catalysts or active ions, substrate alloying, etc. However, the process control of such regulation methods is relatively complex, the improvement of the carburizing layer depth is limited, and it is very easy to introduce coarse network carbides in the top layer, affecting the fatigue wear life of parts. Summary of the invention

[0004] In view of the above situation, the present invention aims to provide a hot forming preparation method for carburized parts and hot formed carburized parts, which can at least solve one of the following technical problems: traditional surface carburizing heat treatment of parts requires extremely long diffusion time in the furnace, low production efficiency and high energy consumption.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] The present invention provides a hot forming preparation method for carburized parts, the preparation method comprising:

[0007] Step 1: Carburizing steel is preformed by hot pressure processing to obtain a component blank;

[0008] Step 2: Cold rough processing is performed on the blank of the component to remove the surface decarburized layer;

[0009] Step 3: Carburize the component blank to obtain a carburized layer with a depth greater than 2 mm;

[0010] Step 4: Carburizing the finished parts and then subjecting them to die forging and subsequent heat treatment to obtain hot-formed carburized parts;

[0011] Step 5: Finish grinding the hot-formed carburized parts to the target dimensions.

[0012] Furthermore, the height H of the component blank in the forming direction in step 1 and the height h of the final component in the forming direction in step 4 meet the following relationship:

[0013]

[0014] Wherein, T is the carburized layer thickness of the component blank in step 3, and t is the carburized layer thickness of the final component.

[0015] Furthermore, the value of H / h ranges from 1.3 to 3.0.

[0016] Furthermore, in step 1, the holding temperature of the hot pressure processing is 1000-1200°C.

[0017] Furthermore, in step 3, the carburizing heating and insulation temperature is 920-960°C.

[0018] Furthermore, in step 3, the carburizing process includes two stages: intensive carburizing and diffusion. The carbon potential in the intensive carburizing stage is not less than 1.0, and the carbon potential in the diffusion stage is not less than 0.8.

[0019] Furthermore, step 4 is performed immediately after step 3 is completed, and the final temperature of the die forging precision forming is not less than 860°C.

[0020] Furthermore, the subsequent heat treatment in step 4 includes quenching, deep cryogenic treatment and low temperature tempering treatment.

[0021] Furthermore, the heating and holding temperature of the quenching treatment is not higher than 860°C.

[0022] The present invention also provides a hot-formed carburized component, which is prepared by the above-mentioned preparation method.

[0023] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0024] a) In the hot forming preparation method of the carburized parts of the present invention, the carburized steel is first preformed to obtain a part blank, and then the part blank is carburized, and then the carburized part blank is subjected to die forging precision forming and heat treatment to obtain a hot formed carburized part; the preformed blank has a large carburizing surface area, which is fully utilized to enable the surface to fully and efficiently absorb the heat-diffused carbon elements during the carburizing process, which can effectively avoid the waste of invalid carbon source atmosphere during the carburizing process, and the final die forging precision forming treatment is performed after carburizing, which can make the carburized layer after the die forging precision forming treatment thicker by 1.1 to 1.7 times, and can significantly reduce the energy consumption of traditional carburizing heat treatment.

[0025] b) In the hot forming preparation method of the carburized parts of the present invention, by accurately controlling the height of the part blank in the forming direction, the height of the final part in the forming direction, the carburized layer thickness of the part blank and other parameters, it can be ensured that the carburized layer thickness of the final part meets the requirements. The method of the present invention can break through the carburizing layer depth limit of 5 to 6 mm in traditional carburizing heat treatment, and can achieve a carburizing layer depth of 6 to 9 mm by adjusting the value of H / h, thereby meeting the carburizing layer thickness requirements of heavy-load wear parts.

[0026] c) Compared with the conventional method of first forming the parts and then performing carburizing treatment, the hot forming preparation method of the carburized parts of the present invention uses the same carburizing furnace time to obtain a deeper final carburized layer depth, which can significantly reduce energy consumption and improve production efficiency. At the same time, the shorter furnace time can avoid excessive grain growth and reduce the grade of network carbides, so as to improve the comprehensive mechanical properties and wear resistance of the carburized layer.

[0027] d) In the hot forming preparation method of the carburized parts of the present invention, during the fine forging process after carburizing, the microscopic grain size of the carburized layer can be further refined, and at the same time, the continuous carbides precipitated at the original austenite grain boundaries during the carburizing process can be divided and crushed to reduce the grade of network carbides, thereby improving the comprehensive mechanical properties and wear resistance of the carburized layer.

[0028] e) The carburized layer of the hot-formed carburized parts of the present invention has fine and uniform grains, no coarse austenite grains, no continuously distributed network carbides, and the carburized layer has excellent comprehensive mechanical properties and wear resistance, for example, the surface hardness can reach above 650HV.

[0029] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the contents particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0031] Figure 1 It is a schematic diagram of the preparation method of the present invention;

[0032] Figure 2 It is the cross-sectional hardness gradient distribution diagram of the carburized layer of the rough part and the carburized layer of the final formed part of the embodiment. DETAILED DESCRIPTION

[0033] Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used to explain the principles of the present invention together with the embodiments of the present invention.

[0034] In the prior art, for carburized layers larger than 3 mm, conventional surface carburizing heat treatment usually requires extremely long diffusion time in the furnace, resulting in low production efficiency and huge energy consumption.

[0035] The present invention provides a hot forming preparation method for a carburized component, comprising:

[0036] Step 1: Carburizing steel is preformed by hot pressure processing to obtain a component blank;

[0037] Step 2: Cold rough processing is performed on the blank of the component to remove the surface decarburized layer;

[0038] Step 3: Carburize the component blank to obtain a carburized layer with a depth greater than 2 mm;

[0039] Step 4: Carburizing the finished parts and then subjecting them to die forging, precision forming and subsequent heat treatment to obtain hot-formed carburized parts;

[0040] Step 5: Finish grinding the hot-formed carburized parts to the target dimensions.

[0041] The thermoforming preparation method of the present invention is as follows Figure 1 shown.

[0042] Specifically, in the above step 1, the hot pressure processing method can be extrusion, forging and rolling, etc.; the formed parts can be shafts, gears and circular rings, etc.

[0043] Specifically, the height H of the component blank in the forming direction in the above step 1 and the height h of the final component in the forming direction in step 4 meet the following relationship:

[0044]

[0045] Among them, H is the height of the component blank in the forming direction, h is the height of the final component in the forming direction, T is the carburized layer thickness of the component blank in step 3, and t is the carburized layer thickness of the final component.

[0046] Considering that too large a value of H / h will cause forging cracks, and too small a value will result in insignificant thickening of the carburized layer, the value of H / h is controlled within the range of 1.3 to 3.0.

[0047] Compared with the prior art, in the hot forming preparation method of carburized parts of the present invention, carburizing steel is first preformed to obtain a part blank, the part blank is then carburized, and then the carburized part blank is precision-formed by die forging and heat-treated to obtain a hot-formed carburized part; the preformed blank has a large carburizing surface area, which enables the surface to fully and efficiently absorb the heat-diffused carbon elements during the carburizing process, which can effectively avoid the waste of invalid carbon source atmosphere during the carburizing process, and the final die forging precision forming treatment is performed after carburizing, which can make the carburized layer after the die forging precision forming treatment thicker by 1.1 to 1.7 times, and can significantly reduce the energy consumption of traditional carburizing heat treatment.

[0048] In the hot forming preparation method of the carburized parts of the present invention, by accurately controlling parameters such as the height of the part blank in the forming direction, the height of the final part in the forming direction, and the carburized layer thickness of the part blank, it can be ensured that the carburized layer thickness of the final part meets the requirements.

[0049] Specifically, in the above step 2, the cold rough processing can be turning, milling, grinding, etc.; the surface decarburization layer is generally within a depth of 0.5 mm.

[0050] Specifically, in the above step 1, if the holding temperature of the hot press processing is too high, it will cause serious decarburization on the surface and a thick decarburization layer; if the holding temperature is too low, it will make it difficult to form the blank parts and prone to forging cracks. Therefore, the holding temperature of the hot press processing is controlled to be 1000-1200°C, such as 1050°C, 1100°C, 1150°C.

[0051] It should be noted that, for a component blank with a carburized layer thickness of less than 2 mm, even with a larger forging ratio, such as H / h=3, a final carburized layer thickness of more than 3.5 mm cannot be achieved, and the requirement for high wear resistance of heavy-loaded parts cannot be met. Therefore, the present invention requires that the carburized layer thickness of the component blank be controlled to be more than 2 mm.

[0052] Specifically, in the above step 3, considering that the carburizing heating and holding temperature of the carburizing treatment is too high, it will lead to coarse austenite grains and easy to form mixed crystals; too low temperature will lead to insufficient carburizing rate. Therefore, the carburizing heating and holding temperature is controlled to be 920-960°C, such as 930°C, 940°C, 950°C.

[0053] Specifically, in the above step 3, the carburizing process includes two stages: intensive carburizing and diffusion. The carbon potential in the intensive carburizing stage is not less than 1.0, and the carbon potential in the diffusion stage is not less than 0.8. The depth of the carburized layer takes the carbon content of 0.5wt% as the critical value, and the depth of the carburized layer is greater than 2mm.

[0054] Specifically, the above step 4 is performed immediately after the step 3 is completed, that is, the component blank in step 3 is immediately subjected to die forging precision forming after being taken out of the furnace, and the final temperature of the die forging precision forming is not less than 860°C. This is because when the forging ratio H / h reaches 2 or more, if the final forging temperature of the die forging precision forming is too low, forging cracks are likely to occur.

[0055] Specifically, in the above step 4, the forging ratio H / h of die forging precision forming is controlled at 1.3 to 3. If it is too large, forging cracks will occur, and if it is too small, the thickening effect of the carburized layer will not be obvious.

[0056] Specifically, the subsequent heat treatment in the above step 4 includes quenching, deep cryogenic treatment and low temperature tempering treatment.

[0057] Specifically, the quenching treatment in the above step 4 can be performed immediately after the die forging precision forming, or after the die forging precision forming is air-cooled to room temperature, and then heated, kept warm and quenched.

[0058] It should be noted that if the workpiece can be quenched directly in a very short time after die forging, such as 20 seconds, it can save energy and achieve the purpose of preheating and quenching. If the workpiece cannot be transferred to the quenching production line for quenching within 20 seconds after die forging, network carbides will appear in the carburized layer after die forging, which will deteriorate the performance of the carburized layer. At this time, the parts need to be reheated to the quenching temperature and then quenched.

[0059] Specifically, in the above step 4, if the heating and holding temperature of the quenching treatment is too high, the temperature difference between quenching and cooling will be too large, and the parts will deform or crack. If the temperature is too low, the quenching will be incomplete, and a network of carbide will appear, which will deteriorate the performance. Therefore, the reheating and holding temperature of the quenching treatment is controlled not to be higher than 860°C.

[0060] Specifically, in the above step 4, if the quenching treatment is left for too long, the residual austenite in the high carbon area of ​​the surface will be stabilized at room temperature and will no longer undergo deep transformation, thereby reducing the final surface hardness. Therefore, the cryogenic treatment is controlled to be carried out within 12 hours after quenching.

[0061] Specifically, in the above step 4, if the temperature of the cryogenic treatment is too high and the time is too short, the residual austenite transformation will be incomplete, resulting in insufficient hardness of the final surface layer; if the temperature is too low and the time is too long, the stress of the quenched martensite structure will be too large, and internal microcracks will easily appear, which will deteriorate the wear resistance of the surface layer and even cause the surface layer to crack and the parts to be scrapped. Therefore, the temperature of the cryogenic treatment is controlled not to be higher than -60°C and not lower than -120°C, and the cryogenic treatment time is not less than 6 hours and not more than 24 hours. For example, the temperature of the cryogenic treatment is -70 to -110°C, such as -80°C, -90°C, and -100°C, and the time of the cryogenic treatment is 6 to 24 hours, such as 8h, 10h, 12h, 14h, 16h, 18h, 20h, and 22h.

[0062] Specifically, in the above step 4, the holding temperature of the low-temperature tempering treatment is controlled to be 170°C to 200°C (for example, 180°C, 190°C, 200°C), and the holding time of the low-temperature tempering is more than 2 hours, for example, 2 to 8 hours (for example, 4h, 5h, 6h, 7h, 8h).

[0063] Specifically, in the above step 5, the surface removal depth of the fine grinding process is less than 0.2 mm.

[0064] The present invention also provides a hot-formed carburized component, which is prepared by the above-mentioned preparation method.

[0065] Specifically, the carburized layer depth of the hot-formed carburized component of the present invention is 2.3 to 9 mm.

[0066] Specifically, the carburized layer of the hot-formed carburized component of the present invention has fine and uniform grains, no coarse austenite grains, and no continuously distributed network carbides.

[0067] Compared with the prior art, in the hot forming preparation method of carburized parts of the present invention, carburizing steel is first preformed to obtain a part blank, the part blank is then carburized, and then the carburized part blank is precision-formed by die forging and heat-treated to obtain a hot-formed carburized part; the preformed blank has a large carburizing surface area, which enables the surface to fully and efficiently absorb the heat-diffused carbon elements during the carburizing process, which can effectively avoid the waste of invalid carbon source atmosphere during the carburizing process, and the final die forging precision forming treatment is performed after carburizing, which can make the carburized layer after the die forging precision forming treatment thicker by 1.1 to 1.7 times, and can significantly reduce the energy consumption of traditional carburizing heat treatment.

[0068] In the hot forming preparation method of the carburized parts of the present invention, by accurately controlling parameters such as the height of the part blank in the forming direction, the height of the final part in the forming direction, and the carburized layer thickness of the part blank, it can be ensured that the carburized layer thickness of the final part meets the requirements.

[0069] Compared with the traditional method of first forming parts and then carburizing them, the hot forming preparation method of the carburized parts of the present invention uses the same carburizing furnace time to obtain a deeper final carburized layer depth, which can significantly reduce energy consumption and improve production efficiency. At the same time, the shorter furnace time can avoid excessive grain growth and reduce the grade of network carbides, so as to improve the comprehensive mechanical properties and wear resistance of the carburized layer.

[0070] In the hot forming preparation method of the carburized parts of the present invention, during the fine forging process after carburizing, the micro grain size of the carburized layer can be further refined, and at the same time, the continuous carbides precipitated at the original austenite grain boundaries during the carburizing process can be divided and crushed to reduce the grade of network carbides, thereby improving the comprehensive mechanical properties and wear resistance of the carburized layer.

[0071] The carburized layer of the hot-formed carburized parts of the present invention has fine and uniform grains, no coarse austenite grains, no continuously distributed network carbides, and the carburized layer has excellent comprehensive mechanical properties and wear resistance, for example, the surface hardness can reach above 650HV.

[0072] The advantages of the process of the present invention are demonstrated below with specific examples and comparative examples.

[0073] Example 1

[0074] The present embodiment provides a hot forming preparation method for carburized parts and hot formed carburized parts. The present embodiment is implemented on large-module gears, with a gear module of 40, 11 teeth, and a height of 200 mm. The final carburized layer depth is required to be 3.0 mm.

[0075] The preparation method is as follows:

[0076] Step 1: Use high temperature die forging method to extrude the cylindrical steel billet into a gear blank state with a height of 400 mm;

[0077] Step 2: Grind to remove the oxide scale and decarburized layer on the surface of the gear blank, with a grinding depth of 0.3 mm;

[0078] Step 3: Carburizing the ground gear blank to obtain a carburized layer with a depth of 2.2 mm;

[0079] Step 4: The gear blank after carburizing treatment is subjected to die forging precision forming, and the final temperature of die forging precision forming is not less than 860°C; the height of the formed part is 200mm; the gear part is immediately quenched after die forging; then deep cooling is performed within 3 hours, the deep cooling temperature is -80°C, and the deep cooling holding time is 6 hours; then low-temperature tempering is performed at 180°C, and the tempering time is 6 hours;

[0080] Step 5: The gear parts are finely ground, with a surface grinding removal depth of 0.2 mm to obtain the final finished parts.

[0081] In this embodiment, the size of the final finished part may have a tolerance within 0.3 mm.

[0082] In this embodiment, the carburizing layer depth of the gear part finally formed is 3 mm. The carburizing process in step 3 includes two stages: strong carburizing and diffusion. The carbon potential in the strong carburizing stage is 1.1, and the carbon potential in the diffusion stage is 0.85. The carburizing temperature is 930°C, and the total carburizing furnace time is 30 hours.

[0083] The carburized layer of the final finished part of this embodiment has no coarse austenite grains, no continuously distributed network carbides, the grade is level 2, and the surface hardness can reach 660 HV.

[0084] Example 2

[0085] The present embodiment provides a hot forming preparation method for carburized parts and hot formed carburized parts. The present embodiment is implemented on a large diameter bearing outer support ring. The outer circle diameter of the outer support ring is 3m, the inner circle diameter is 2.6m, the wall thickness is 20mm, the height is 300mm, and the final inner carburized layer depth is required to be 3.5mm.

[0086] The preparation method is as follows:

[0087] Step 1: Using a high temperature upsetting rolling method, the cylindrical steel billet is formed into a ring blank state with a height of 700 mm;

[0088] Step 2: Use rough turning to remove the oxide scale and decarburized layer on the surface of the ring blank, and the grinding depth is 0.8mm;

[0089] Step 3: Carburizing the ground ring blank at high temperature to obtain a carburized layer with a depth of 2.4 mm;

[0090] Step 4: The carburized ring blank is subjected to die forging precision forming, and the final temperature of die forging precision forming is not less than 860°C; the height of the formed part is 300mm; the part is immediately quenched after die forging; and then deep-cooled within 3 hours, the deep-cooling temperature is -100°C, and the deep-cooling holding time is 6 hours; followed by low-temperature tempering at 180°C, and the tempering time is 6 hours;

[0091] Step 5: The gear parts after die forging are finely ground, with a surface grinding removal depth of 0.2 mm to obtain the final finished parts.

[0092] In this embodiment, the size of the final finished part may have a tolerance within 0.3 mm.

[0093] In this embodiment, the carburized layer depth of the final formed part is 3.5 mm. The carburizing process in step 3 includes two stages: intensive carburizing and diffusion. The carbon potential in the intensive carburizing stage is 1.2, and the carbon potential in the diffusion stage is 0.85. The carburizing temperature is 930°C, and the total carburizing furnace time is 40 hours.

[0094] The carburized layer of the final finished part of this embodiment has no coarse austenite grains and no continuously distributed network carbides, and the grade is level 2, and the surface hardness can reach above 650 HV.

[0095] Figure 2 This is a cross-sectional hardness gradient distribution diagram of the carburized layer of the blank part and the carburized layer of the final formed part of this embodiment. It can be seen from the figure that the depth of the carburized layer can be significantly increased through forging precision forming.

[0096] The inventor has conducted a lot of research during the research process, and now uses some solutions with poor performance as comparative examples.

[0097] Comparative Example 1

[0098] This comparative example provides a method for preparing a carburized component and a hot-formed carburized component, and the implementation objects and technical requirements are the same as those of Example 1. The preparation method is as follows:

[0099] Step 1: Using a high temperature die forging method, the cylindrical steel billet is extruded into a gear shape with a height of 200 mm;

[0100] Step 2: Use grinding to remove the oxide scale and decarburized layer on the surface of the formed gear, with a grinding depth of 0.3mm;

[0101] Step 3: Carburizing the ground gear blank at high temperature to obtain a carburized layer with a depth of 3.2 mm;

[0102] Step 4: Quench the carburized parts and then deep cool them within 3 hours at a temperature of -80°C and a holding time of 6 hours; then perform low-temperature tempering at 180°C for 6 hours;

[0103] Step 5: The gear parts are finely ground, with a surface grinding removal depth of 0.2 mm to obtain the final finished parts.

[0104] In this comparative example, the carburized layer depth of the final formed part is 3 mm. The carburizing process in step 3 includes two stages: intensive carburizing and diffusion. The carbon potential in the intensive carburizing stage is 1.1, and the carbon potential in the diffusion stage is 0.85. The carburizing temperature is 930°C, and the total carburizing furnace time is 72 hours.

[0105] The carburized layer of the final formed part of this comparative example has a mixed crystal structure, a continuously distributed network of carbides, a grade of three, and a surface hardness of less than 650 HV.

[0106] It can be seen that compared with Example 1, the carburizing time in the furnace of this comparative example is 2.4 times that of Example 1, the energy consumption is huge, the production efficiency is low, and mixed crystals and continuous network carbides are easily formed in the carburized layer, which deteriorates the mechanical properties of the carburized layer.

[0107] Comparative Example 2

[0108] This comparative example provides a method for preparing a carburized component and a hot-formed carburized component, and the implementation objects and technical requirements are the same as those of Example 1. The preparation method is substantially the same as that of Example 1, except that:

[0109] In step 1, the height is 250 mm;

[0110] In step 3, a carburized layer with a depth of 1.5 mm is obtained;

[0111] The carburized layer depth of the final formed part of this comparative example is 1.65 mm. Compared with the carburized layer depth in step 3, the thickening effect is not obvious and the required carburized layer depth cannot be reached.

[0112] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for hot forming a carburized component, characterized in that: The preparation method comprises: Step 1: Carburizing steel is preformed by hot pressure processing to obtain a component blank; Step 2: Cold rough processing is performed on the blank of the component to remove the surface decarburized layer; Step 3: Carburize the component blank to obtain a carburized layer with a depth greater than 2 mm; Step 4: Carburizing the finished parts and then subjecting them to die forging, precision forming and subsequent heat treatment to obtain hot-formed carburized parts; Step 5: Finish grinding the hot-formed carburized parts to the target dimensions.

2. The preparation method according to claim 1, characterized in that: The height H of the component blank in the forming direction in step 1 and the height h of the final component in the forming direction in step 4 meet the following relationship: √H / h=(1.02~1.05)t / T Wherein, T is the carburized layer thickness of the component blank in step 3, and t is the carburized layer thickness of the final component.

3. The preparation method according to claim 2, characterized in that: The value of H / h ranges from 1.3 to 3.

0.

4. The preparation method according to claim 1, characterized in that: In the step 1, the heat preservation temperature of the hot pressure processing is 1000-1200°C.

5. The preparation method according to claim 1, characterized in that: In step 3, the carburizing heating and insulation temperature is 920-960°C.

6. The preparation method according to claim 1, characterized in that: In step 3, the carburizing process includes two stages: intensive carburizing and diffusion. The carbon potential in the intensive carburizing stage is not less than 1.0, and the carbon potential in the diffusion stage is not less than 0.

8.

7. The preparation method according to claim 1, characterized in that: The step 4 is performed immediately after the step 3 is completed, and the final temperature of the die forging precision forming is not less than 860°C.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The subsequent heat treatment in step 4 includes quenching, deep cryogenic treatment and low temperature tempering treatment.

9. The preparation method according to claim 8, characterized in that: The heating and heat preservation temperature of the quenching treatment is not higher than 860°C.

10. A hot formed carburized component, characterized in that: The preparation method is described in any one of claims 1 to 9.

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